DE60035409T2 - STEAM COMPRESSION SYSTEM AND METHOD - Google Patents

Abstract

A vapor compression system ( 10 ) including an evaporator ( 16 ), a compressor ( 12 ), and a condenser ( 14 ) interconnected in a closed-loop system. In one embodiment, a multifunctional valve ( 18 ) is configured to receive a liquefied heat transfer fluid from the condenser ( 14 ) and a hot vapor from the compressor ( 12 ). A saturated vapor line ( 28 ) connects the outlet of the evaporator ( 16 ) and is sized so as to substantially convert the heat transfer fluid exiting the multifunctional valve ( 18 ) into a saturated vapor prior to delivery to the evaporator ( 16 ). The multifunctional valve ( 18 ) regulates the flow of heat transfer fluid by monitoring the temperature of the heat transfer fluid returning to the compressor ( 12 ) through a suction line ( 30 ) coupling the evaporator ( 16 ) outlet to the compressor ( 12 ) inlet. In one preferred embodiment, a bifurcated liquid line connects the condenser ( 14 ) outlet to the first inlet of an multifunctional valve and the inlet of a metering unit.

Description

The This invention relates generally to vapor compression systems and specifically on mechanically controlled cooling systems, the forward flow Use defrost cycles.

BACKGROUND OF THE INVENTION

In a closed cycle vapor compression cycle the heat transfer fluid in the condenser, its state changes from vapor to liquid, releasing heat and changes its state of liquid in the evaporator to steam while being the evaporation heat is absorbed. A typical vapor compression refrigeration system includes a compressor for pumping a heat transfer fluid, e.g. Freon, to a condenser where heat is discharged when the vapor condenses into a liquid. The liquid flows through a fluid line to a thermostatic expansion valve, where the heat transfer fluid undergoes a volume expansion. The heat transfer fluid is a liquid-vapor mixture when leaving the thermostatic expansion valve of low quality. The term "liquid-vapor mixture of low quality, "as he uses here is, refers to a heat transfer fluid of low pressure in a liquid Condition with a small amount of vapor gas, which is the residual heat transfer fluid cools, while the heat transfer fluid in a supercooled Condition remains. The expanded heat transfer fluid then flows in an evaporator, where the liquid coolant vaporized at low pressure, absorbing heat while it is a change of state of liquid to steam. The heat transfer fluid, now in the vapor state, flows through a suction line back to the compressor. Sometimes leaves the heat transfer fluid the evaporator not in a vapor state, but rather in a overheated one Vapor state.

To depends on one aspect the efficiency of the vapor compression cycle from the ability of the system, the heat transfer fluid as a high pressure fluid after leaving the condenser. The chilled High pressure fluid must over the long cooling pipes, extending between the condenser and the thermostatic expansion valve extend in the liquid Condition remain. The correct operation of the thermostatic expansion valve depends from a certain amount of liquid heat transfer fluid, which happens the valve. When the high pressure liquid through an opening in the thermostatic expansion valve, that suffers Fluid a pressure loss as soon as the fluid expands through the valve. Cool at the low pressure the fluid an additional Amount like a small amount of evaporating gas, forming and that cools Bulk of the heat transfer fluid, which in liquid Shape is. The term "evaporation gas" as used here is used to reduce the pressure in an expansion device to describe how B. a thermostatic expansion valve, when a liquid passing through the valve quickly into a gas is transformed and the remaining heat transfer fluid cools, which corresponding to the ambient temperature in liquid form.

The Liquid-vapor mixture of low quality passes the entrance of cooling coils inside the evaporator. As the fluid travels through the snakes, it initially absorbs a small amount Amount of heat, while it warms up and reaches the point where there is a liquid-vapor mixture of high quality becomes. The term "liquid-vapor mixture high quality, "as he uses here is, refers to a heat transfer fluid, which also in the liquid State as well as in the vapor state with the same enthalpy remains, indicating that the pressure and temperature of the heat transfer fluid to corrode with each other. A liquid-vapor mixture high quality is able to heat to absorb very efficiently as it is in a state change. The heat transfer fluid absorbs then heat from the environment and starts to cook. The cooking process within The evaporator snakes produce a saturated vapor within the Snakes that continue to heat absorbed from the environment. Once the fluid is completely boiled off is, leaves it the rest of the cooling coil as cold steam. Once the fluid is completely transformed into cold steam is, it absorbs very little heat. While the last stages of the cooling coil changes the heat transfer fluid in a overheated Steam condition and becomes a superheated Steam. As defined herein, the heat transfer fluid becomes a "superheated steam" when minimum heat is added to the heat transfer fluid Heat transfer fluid added will, while it is in the vapor state, whereby the temperature of the heat transfer fluid over the Point at which it assumed the vapor state while it a similar one Maintains pressure. The overheated Steam is then returned to the compressor through a suction line where the vapor compression cycle continues.

For highly efficient operation, the heat transfer fluid should change its status from a liquid to a vapor in a large section of the cooling coils within the evaporator. As the heat transfer fluid changes state from a liquid to a vapor, it absorbs one much energy when the molecules change from a liquid to a gas, absorbing latent heat of vaporization. In contrast, relatively little heat is absorbed while the fluid is in the liquid state or while the fluid is in the vapor state. Thus, the optimum cooling efficiency depends on precise control of the heat transfer fluid through the thermostatic expansion valve to ensure that the fluid makes a state change in as long a length of the cooling coil as possible. When the heat transfer fluid enters the evaporator in a cooled liquid state and leaves the evaporator in a vapor state or a superheated vapor state, the cooling efficiency of the evaporator is reduced because a substantial part of the evaporator contains liquid which is in a state absorbing very little heat , For optimum cooling efficiency, a substantial portion or part of the evaporator should contain fluid which is both liquid and vapor. To ensure optimum cooling efficiency, the heat transfer fluid should be a high quality liquid-vapor mixture as it enters and exits the evaporator.

The Thermostatic expansion valve plays in flow regulation of the heat transfer fluid the closed circulatory system plays an important role. Before in the evaporator a cooling effect can be produced, the heat transfer fluid from a High temperature liquid, which leaves the evaporator, be cooled by a pressure loss to a range that is suitable for one Evaporation temperature. The flow of liquid at low pressure to the evaporator is through the thermostatic expansion valve measured to a maximum cooling efficiency in the evaporator upright. Typically regulated mechanical thermostatic expansion valve as soon as the operation has stabilized, the flow of heat transfer fluid by the temperature of the heat transfer fluid monitored in the suction line near the outlet of the evaporator. When leaving the thermostatic expansion valve is the heat transfer fluid in the form of a liquid at low pressure with a small amount of steam gas. The presence of steam gas provides a cooling effect on the balance of the heat transfer fluid in his liquid Condition, and forms a liquid-vapor mixture low quality. A temperature sensor is attached to the suction pipe to reduce the amount of overheating to measure the heat transfer fluid suffers when it leaves the vaporizer. Superheat is the amount of heat which added to the steam is after the heat transfer fluid Completely has boiled out and no liquid more remains in the suction line. Because of the overheated Steam very little heat is absorbed, the thermostatic expansion valve measures the Flow of heat transfer fluid, to minimize the amount of superheated steam formed in the evaporator. Accordingly, the thermostatic expansion valve determines Amount of liquid with low pressure, which flows into the evaporator, adding the measure of overheating monitored the leaving the evaporator steam.

In addition to the need to control the flow of heat transfer fluid through the regulating closed loop system depends on the optimal operating efficiency of the cooling system from a periodic defrost of the evaporator. periodic Defrosting the evaporator is necessary to get rid of ice that is going on during of the operation on the evaporator coils. When ice or Forming frost on the evaporator, it interferes with the passage of air through the evaporator coils and reduces heat transfer efficiency. In commercial systems such. B. Refrigerated counters can be the formation of Ripe reduce the amount of air flow in such a way that in the refrigerated cabinet no air curtain forms. In commercial systems like food coolers and like that, it is often necessary Defrost the evaporator every few hours. Different defrosting methods exist, so the stopping method, where the cooling cycle stopped and the Evaporator is defrosted with air from ambient temperature. In addition will be electric defrosting with electric defrost used where electrical heating elements are arranged around the evaporator and electric current is sent through the heating coils to the To melt ripe.

In addition to The defrost systems with standstill cooling systems have been developed, which to defrost the evaporator to the relatively high temperature support the heat transfer fluid leaving the compressor. at These techniques use high temperature steam directly from the compressor redirected to the evaporator. In one technique, the flow of the High-temperature steam passed into the intake and the system is essentially operated backwards. In other techniques, the high temperature steam becomes a special one Line pumped, which leads directly from the compressor to the evaporator the only purpose of passing high-temperature steam to the evaporator periodically defrost. additionally Other complex processes have been developed that affect many Devices inside the cooling system support, like z. B. Bypass valves, bypass lines, heat exchangers, etc ..

US 2,707,868 describes a cooling system which provides efficient and uniform cooling by providing even distribution of a liquid coolant in the tubes of a vaporiser Fers provides. This is accomplished through the use of a powerful condenser that delivers liquid coolant through the supply head of the evaporator tubes.

WO 93/06422 describes a coolant cooling unit that interrupts the normal cooling cycle to allow a low-temperature liquid to enter the expansion device. This provides a reduced temperature and a reduced gas pressure as a supply to the inlet side of the compressor, which should reduce the energy requirement and the operating costs of the compressor.

at an attempt to better operating efficiency of conventional Vapor compression cooling systems To reach, develops the cooling industry Systems with increasing complexity. Sophisticated computerized thermostatic Expansion valves have been developed while trying to get a better one Control of the heat transfer fluid to reach through the evaporator. In addition, complex valves and Pipe systems designed to defrost the evaporator faster to maintain high heat transfer rates to obtain. While these systems have reached different levels of success are increasing the system cost as dramatic as the complexity of the system increases. Accordingly, there is a need for an efficient refrigeration system. which is installed at low cost and with high efficiency can be operated.

SUMMARY OF THE INVENTION

The The present invention provides a cooling system which maintains a high operating efficiency by being saturated Steam in the entrance of an evaporator supplies. The term "Saturated Steam, "as he here is used, refers to a heat transfer fluid, which is both in the liquid State as well as in the vapor state with the same enthalpy and indicating that pressure and temperature of the heat transfer fluid are related korellieren. saturated Steam is a liquid-vapor mixture high quality. Being more saturated Steam supplied to the evaporator is, the heat transfer fluid occurs both in the liquid as well as in the vapor state in the evaporator coils. Thus, will the heat transfer fluid delivered to the evaporator in a physical state in which the fluid has maximum heat can be absorbed. additionally to the highly efficient operation of the evaporator provides in a preferred embodiment the invention, the cooling system a simple means for defrosting the evaporator available. One Multifunctional valve is used, which contains separate passages that lead into a common chamber. In operation, the multifunction valve can either be a saturated Steam for a cooling or a high-temperature steam for direct a defrost to the evaporator.

According to one The first aspect of the present invention is a vapor compression system to disposal comprising a compressor for increasing pressure and temperature a heat transfer fluid, a first drain pipe connecting the compressor to a condenser couples, a fluid line, the capacitor with a first input of an expansion valve coupled, wherein the expansion valve is configured so that the Heat transfer fluid expanded to form an expanded heat transfer fluid, a saturated steam line, which couples an output of the expansion valve to an evaporator, and a suction line coupling the evaporator to the compressor, characterized in that a heat source is expanded on the Heat transfer fluid is applied before entering the evaporator, creating a Conversion of a substantial part of the heat transfer fluid into one saturated Steam is achieved before entering the evaporator, (a) where the compressor and / or the condenser in close proximity to the expansion valve lie so that the liquid line relative short and the saturated steam line relatively longer as the liquid line is, being the heat source the heat that is generated by the compressor and / or the condenser, or (b) wherein the heat source an active heat source is.

According to a second aspect of the present invention there is provided a vapor compression system comprising a compressor for increasing the pressure and the temperature of a heat transfer fluid, a first discharge line connecting the compressor to a condenser, a liquid line connecting the condenser to a first input of a condenser The expansion valve connects, wherein the expansion valve is designed so that the heat transfer fluid can expand to form an expanded heat transfer fluid, a saturated vapor line that connects an outlet of the expansion valve with an evaporator, a suction line that connects the evaporator to the compressor , characterized in that a heat source is applied to the expanded heat transfer fluid prior to its entry into the evaporator, whereby a conversion of a substantial portion of the heat transfer fluid into a saturated vapor prior to its entry itt be reached in the evaporator, where wherein the expansion valve is part of a recovery valve, which recovery valve comprises a first inlet providing fluid access for the heat transfer fluid into a common chamber, and a first outlet providing fluid exit for the heat transfer fluid from the common chamber, and wherein a portion of the the first outlet conduit is disposed adjacent to the common chamber, the heat source being heat generated by the compressor and / or the condenser and transmitted to the common chamber through the first outlet conduit.

In the aforementioned aspects of the present invention converts the heat source the heat transfer fluid from a liquid-vapor mixture low quality in a liquid-vapor mixture high quality or in a saturated Steam. Typically, at least 5% of the heat transfer fluid will be before entry evaporated in the evaporator. In one embodiment of the invention sits the expansion valve in the multi-function valve, which has a first inlet for receiving the heat transfer fluid in the liquid state and a second inlet for receiving the heat transfer fluid in the vapor state includes. The multi-function valve also has passages, the connect the first and second inlets to a common chamber. Valve spool, which are positioned in the passages, allow the independent one Interrupting the flow of heat transfer fluid in every passage. The possibility, the flow of saturated Steam and high-temperature steam through the cooling system independently too control, generates a high operating efficiency.

The increased Operating efficiency makes it possible the cooling system with relatively small amounts of heat transfer fluid to load, with the cooling system but relatively large heat loads can handle.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic representation of a vapor compression system arranged according to an embodiment of the invention;

2 is a side view, partially in section, of a first side of a multi-function valve according to an embodiment of the invention;

3 is a side view, partially in section, of a second side of the multi-function valve of 2 ;

4 is an exploded view of a multi-function valve according to an embodiment of the invention:

5 Fig. 10 is a schematic view of a vapor compression system according to another embodiment of the invention;

6 is an exploded view of the multi-function valve according to another embodiment of the invention;

7 Fig. 10 is a schematic view of a vapor compression system according to still another embodiment of the invention;

8th FIG. 10 is an enlarged cross-sectional view of a portion of the vapor compression system of FIG 7 ;

9 Fig. 12 is a schematic view, partly in section, of a recovery valve according to an embodiment of this invention;

10 Fig. 12 is a schematic view, partly in section, of a recovery valve according to still another embodiment of this invention;

11 Fig. 12 is a plan view, partly in section, of a valve body on a multi-function valve or multifunction device according to another embodiment of the present invention;

12 is a side view of the valve body of the multi-function valve of 11 ;

13 is an exploded view, partially sectioned, of the multi-function valve or multi-function device 11 and 12 ;

14 is an enlarged view of a part of the multi-function valve or the multi-function device of 12 ;

15 Fig. 12 is a plan view, partly in section, of a valve body on a multi-function valve or multifunction device according to another embodiment of the present invention; and

16 Figure 11 is a schematic view of a vapor compression system arranged in accordance with yet another embodiment of the invention.

DETAILED DESCRIPTION THE PREFERRED EMBODIMENTS

An embodiment of a vapor compression system 10 , arranged according to an embodiment of the invention, is in 1 shown. The cooling system 10 includes a compressor 12 , a capacitor 14 , an evaporator 16 and a multi-function valve 18 , compressor 12 is with the capacitor 14 through an outlet line 20 connected. Multi-function valve 18 is connected to the condenser through a liquid line 22 that with a first inlet 24 of the multi-function valve 18 connected is. In addition, the multifunction valve 18 at a second inlet 26 with the outlet pipe 20 connected. A saturated steam line 28 connects the multifunction valve 18 with the evaporator 16 and a suction line 30 connects the outlet of the evaporator to the inlet of the compressor 12 , A temperature sensor 32 is on the suction line 30 attached and operationally connected to the multifunction valve 18 , According to the invention are compressor 12 , Capacitor 14 , Multifunction valve 18 and temperature sensor 32 in a control unit 34 accommodated. Accordingly, the evaporator 16 in a cooling housing 36 accommodated. In a preferred embodiment of the invention are compressor 12 , Capacitor 14 , Multifunction valve 18 , Temperature sensor 32 and evaporator 16 all in a cooling housing 36 accommodated. In a further preferred embodiment of the invention, the vapor compression system comprises a control unit 34 and a cooling housing 36 , where compressor 12 and capacitor 14 in the control unit 34 are housed and being evaporators 16 , Multifunction valve 18 and temperature sensor 32 in the cooling housing 36 are housed.

The Vapor compression system of the present invention may be substantially each commercially available available Heat transfer fluid use, including coolants such as For example, chlorofluorocarbons such as R-12, which is a dichlorodifluoromethane R-22, which is a monochlorodifluoromethane, R-500, which is an azeotropic coolant from R-12 and R-152a, R-503, which is an azeotropic refrigerant from R-23 and R-13, and R-502, which is an azeotropic refrigerant from R-22 and R-115. The vapor compression system of the present Invention can also use coolant use such. But not limited to coolant R-13, R-113, 141b, 123a, 123, R-114 and R-11. additionally For example, the vapor compression system of the present invention may include coolant use such. Hydrochlorofluorocarbons such as 141b, 123a, 123 and 124, hydrofluorocarbons such as R-134a, 134, 152, 143a, 125, 32, 23 and azeotropic HFCs such as AZ-20 and AZ-50 (commonly referred to as R-507 is known). Mixed coolants such as MP-39, HP-80, FC-14, R-717 and HP-62 (commonly known as R-404a) in the vapor compression system of the present invention as well as a coolant be used. Accordingly, it should be noted that the special coolant or the special combination of coolants used in the present Invention is not critical to the operation of the present invention Invention, since the invention with apparently all coolants with greater system efficiency should work as it with any prior known vapor compression system possible which is the same coolant used.

In operation, the compressor compresses 12 the heat transfer fluid at relatively high pressure and temperature. Temperature and pressure to which the heat transfer fluid through the compressor 12 are dependent on the specific size of the cooling system 10 and the cooling load requirements of the system. compressor 12 pumps the heat transfer fluid into the outlet line 20 and in the condenser 14 , As will be described in more detail below, during the cooling operation, the second inlet is 26 closed and the entire outlet of the compressor is through the condenser 14 pumped.

In the condenser 14 For example, a medium such as air, water or a second coolant is blown against the coils in the condenser and causes the pressurized heat transfer fluid to change to the liquid state. The temperature of the heat transfer fluid falls by 10 to 40 ° F (5.6 to 22.2 ° C), depending on the particular heat transfer fluid or glycol or the like, since the latent heat in the fluid is expelled during the condensation process. The capacitor 14 discharges the liquefied heat transfer fluid into the liquid line 22 , As in 1 shown, the liquid line opens 22 directly into the multifunction valve 18 , Because the liquid line 22 is relatively short, the temperature of the pressurized fluid passing through the fluid line rises 22 is not essential, while from the condenser 14 to the multifunction valve 18 flows. By the cooling system 10 is configured so that it has a short fluid line, provides the cooling system 10 advantageously, considerable amounts of low temperature, high pressure heat transfer fluid into the multi-function valve 18 , Because the fluid does not migrate over a long distance, once it has been converted into a high pressure liquid, it goes through the inevitable heating of the liquid before entering the multifunction valve 18 occurs, or lost by loss of fluid pressure little heat absorbing ability. While in the aforementioned embodiments of the invention, the cooling system has a relatively short liquid line 22 is used, it is possible to implement the advantages of the present invention also in a refrigeration system having a relatively long liquid line 22 used as will be described below. The heat transfer fluid coming out of the condenser 14 comes, enters the multifunction valve 18 at a first inlet 22 and undergoes volume expansion at a rate determined by the temperature of the suction line 30 at the temperature sensor 32 is determined. Multi-function valve 18 discharges the heat transfer fluid as saturated vapor into a saturated vapor line 28 , The temperature sensor 22 reports the temperature information through a control line 33 to the multifunction valve 18 ,

Professionals will recognize that a cooling system 10 can be used in a variety of applications to control the temperature of a housing, such. B. a refrigerator housing, are stored in the perishable food. Where, for example, a cooling system 10 is used to control the temperature of a refrigerator housing with a cooling load of about 12,000 Btu / hr (84 g cal / s), the compressor delivers 12 about 3 to 5 lbs / min (1.36 to 2.27 kg / min) of R-12 at a temperature of about 110 ° F (43.3 ° C) to about 120 ° F (48.9 ° C) and a pressure of about 150 lbs / in ² (1.03 E5 N / m ² ) to about 180 lbs / in ² (1.25 E5 N / m ² ).

In accordance with a preferred embodiment of the invention, the saturated vapor line is 28 dimensioned such that the low pressure fluid, which in the saturated steam line 28 is essentially converted to a saturated vapor while passing through the saturated steam line 28 emigrated. In one embodiment, the saturator vapor line is 28 dimensioned to be about 2500 ft / min (76 m / min) to 3700 ft / min (1128 m / min) of a heat transfer fluid, such as water. B. R-12 or the like and has a diameter of about 0.5 to 1.0 inches (1.27 to 2.54 cm) and a length of about 90 to 100 feet (27 to 30.5 m) , As will be described in more detail below, the multi-function valve includes 18 a common chamber immediately in front of the outlet. The heat transfer fluid experiences additional volume expansion as it enters the common chamber. The additional volume expansion of the heat transfer fluid in the common chamber of the multi-function valve 18 is equivalent to effectively increasing the line size of the saturator vapor line 28 around 225%.

professionals will also recognize that the positioning of a volume expansion valve of the Heat transfer fluid in close proximity to the capacitor and the relatively long length of the Fluid line between the point of volume expansion and the evaporator It differs essentially from systems on the state of the art Technology. In a typical prior art system an expansion valve immediately adjacent to the inlet of the evaporator positioned and when a temperature sensor is used, it is in positioned immediately adjacent to the outlet of the evaporator. As described above, such a system can be low in efficiency suffer because considerable areas of the evaporator are a liquid instead of a saturated one Steam included. Fluctuations of the high pressure, the liquid temperature, the heat load or other conditions Effectively affect the efficiency of the evaporator.

In contrast to the prior art, the cooling system of the invention described herein positions a saturator vapor line between the point of volume expansion and the inlet of the evaporator such that portions of the heat transfer fluid are converted to saturated steam before the heat transfer fluid enters the evaporator. By loading the evaporator 16 with a saturated steam, the cooling efficiency is significantly improved. By improving the cooling efficiency of an evaporator such as the evaporator 16 Many advantages are realized by the cooling system. For example, less heat transfer fluid is needed to control the air temperature of the refrigerator housing 36 to control to a desired level. In addition, less electricity is needed to the compressor 12 to drive, resulting in lower operating costs. In addition, the compressor can 12 smaller than a prior art system to handle a comparable cooling load. Moreover, in a preferred embodiment of the invention, it avoids the cooling system, several Kom to place components in the vicinity of the evaporator. By limiting the placement of components within the refrigerator enclosure 36 to a minimum number is the thermal load of the refrigerator housing 36 minimized.

While in the above embodiments of the invention, a multi-function valve 18 in the immediate vicinity of the condenser 14 is positioned, creating a relatively short liquid line 22 and a relatively long saturator vapor line 28 be formed, it is possible to implement the advantages of the present invention, even if a multi-function valve 18 immediately after the inlet of the evaporator 16 is positioned, creating a relatively long liquid line 22 and a relatively short saturator vapor line 28 be formed. For example, in a preferred embodiment of the invention is a multi-function valve 18 immediately adjacent to the inlet of the evaporator 16 positioned, creating a relatively long liquid line 22 and a relatively short saturator vapor line 28 be formed as in 7 shown. To ensure that the heat transfer fluid entering the evaporator 16 entering, which is a saturated vapor, becomes an active heat source 25 at the saturator vapor line 28 attached, as in the 7 - 8th shown. temperature sensor 32 is on the suction line 30 attached and operatively connected to the multifunction valve 18 , where the heat source 25 is sufficiently intense to convert a portion of the heat transfer fluid into steam before the heat transfer fluid into the evaporator 16 entry. That in the evaporator 16 entering heat transfer fluid is converted into a saturated vapor, wherein a portion of the heat transfer fluid in a liquid state 29 and another part of the heat transfer fluid in a vapor state 31 exists as in 8th illustrated. The heat source 25 is an active heat source, ie any heat source intentionally associated with a part of the cooling system 10 is connected, such. B. the saturator vapor line 28 , An active heat source includes, but is not limited to, a source of heat, such as heat. For example, heat generated by an electrical heat source, heat generated using combustion materials, heat generated using solar energy, or another source of heat intentionally and actively applied to a portion of the cooling system 10 is transmitted. A heat source that includes heat that happens to enter a part of the cooling system, or heat that is inadvertently or unrecognized in a part of the cooling system 10 is absorbed either because of poor insulation or for other reasons, is not an active heat source.

In a preferred embodiment of the invention, a temperature sensor monitors 32 the heat transfer fluid coming from the evaporator 16 leaking to ensure that a portion of the heat transfer fluid in a liquid state 29 is if it is the evaporator 16 leaves, as in 8th shown. At least 5% of the heat transfer fluid may be vaporized before the heat transfer fluid enters the evaporator and at least about 1% of the heat transfer fluid is in a liquid state as it exits the evaporator. By ensuring that a portion of the heat transfer fluid is in a liquid state 29 and a steam condition 31 As soon as it enters and leaves the evaporator, it makes the vapor compression system of the present invention the evaporator 16 possible to work with maximum efficiency. The heat transfer fluid may be between about a 1% liquid state and about a 1% superheated vapor state after it is the evaporator 16 leaves.

In addition, while the aforementioned embodiments, a temperature sensor 32 to monitor the state of the heat transfer fluid leaving the evaporator, any meter known to those skilled in the art can be used which can determine the state of the heat transfer fluid leaving the evaporator, such. As a pressure sensor or a sensor which measures the density of the fluid. In addition, while in the aforementioned embodiments, the measuring device can control the state of the heat transfer fluid containing the evaporator 16 leaves, monitors, the measuring device also at any point or at the evaporator 16 be positioned to the state of the heat transfer fluid to any point in or at the evaporator 16 to monitor around.

In 2 is a side view, partially cut, of a multi-function valve 18 shown. Heat transfer fluid enters the first inlet 24 and flows through a first passage 38 to a common chamber 40 , An expansion valve 42 is in the first passage 38 near the first inlet 24 positioned. expansion valve 42 measures the flow of heat transfer fluid through the first passage 38 by means of a membrane (not shown) housed in an upper valve housing 44 , expansion valve 42 can be any device known to those skilled in the art that can be used to measure the flow of heat transfer fluid, such as, for example, B. a thermostatic expansion valve, a capillary tube or a pressure control. A control line 33 is with an entrance 62 connected in an upper housing valve 44 is housed. Signals passing through the control line 33 be reported, activate the membrane in the upper valve housing 44 , The membrane moves a valve device 54 (in 4 ) to control the amount of heat transfer fluid coming from the first inlet 24 in an expansion chamber 52 (in 4 shown) occurs. A shut-off valve 46 is in the first passage 38 near the common chamber 40 positioned. shut-off valve 46 may be a solenoid valve which is capable of stopping the flow of heat transfer fluid through the first passage in response to an electrical signal.

In 3 is a side view, partially cut, a second side of a multi-function valve 18 shown. A second passage 48 connects the second inlet 26 with the common chamber 40 , A check valve 50 is in the second passage 48 near the common chamber 40 positioned. In a preferred embodiment of the invention, the check valve 50 a solenoid valve capable of receiving, upon receipt of an electrical signal, the flow of heat transfer fluid through the second passage 48 to end. The common chamber 40 discharges the heat transfer fluid from the multifunction valve 18 through an outlet 41 ,

An exploded perspective view of a multi-function valve 18 is in 4 shown. It can be seen that the expansion valve 42 adjacent the first inlet 22 , an expansion chamber 52 , a valve assembly 54 and an upper valve housing 44 includes. valve assembly 54 is actuated by a diaphragm (not shown) located in the upper valve housing 44 is housed. First and second tubes 56 and 58 are between the expansion chamber 52 and the valve body 60 positioned. check valves 46 and 50 are on a valve body 60 assembled. According to the invention, a cooling system 10 be operated in a defrost mode by blocking valve 46 closed and shut-off valve 50 is opened. In defrost mode, hot heat transfer fluid enters the second inlet 26 and flows through the second passage 48 and flows into the common chamber 40 , The high temperature vapors pass through outlet 41 off and go through the saturator vapor line 28 to the evaporator 16 , The high-temperature steam has a temperature sufficient to the temperature of the evaporator 16 to increase by about 50 to 120 ° F (27.8 to 66.7 ° C). The temperature rise is sufficient to frost from the evaporator 16 to eliminate and restore the heat transfer rate to desired operating levels.

While the aforementioned embodiments, a multi-function valve 18 Use it to expand the heat transfer fluid before entering the evaporator 16 occurs, any thermostatic expansion valve or throttle valve, such. B. expansion valve 42 or even recovery valve 19 used to expand the heat transfer fluid before entering the evaporator 16 entry.

According to the invention, a heat source 25 applied to the heat transfer fluid after the heat transfer fluid is the expansion valve 42 happens and before the heat transfer fluid enters the inlet of the evaporator 16 to convert the heat transfer fluid from a low quality liquid vapor mixture into a high quality liquid vapor mixture or a saturated vapor. In a preferred embodiment of the invention, the heat source 25 to the multifunction valve 18 created. In another preferred embodiment of the invention, the heat source 25 to the recovery valve 19 created as in 9 shown. The recovery valve 19 includes a first inlet 124 that with a fluid line 22 connected, and a first outlet 159 that with a saturator steam pipe 28 connected is. Heat transfer fluid passes through the first inlet 124 of the recovery valve 19 in a common chamber 140 one. An expansion valve 142 is near the first inlet 124 positioned to the heat transfer fluid, which in the first inlet 124 occurs to expand from a liquid state to a low quality liquid-vapor mixture. A second inlet 127 is with the outlet pipe 20 connected and receives heat transfer fluid of high temperature, which is the compressor 12 leaves. High temperature heat transfer fluid exiting a compressor enters the second inlet 127 and flows through the second passage 123 , Second passage 123 is with the second inlet 127 and the second outlet 130 connected. Part of the second passage 123 is adjacent to the common chamber 140 positioned.

While the high temperature heat transfer fluid of the common chamber 140 Heat from the high temperature heat transfer fluid from the second passage is approached 123 to the common chamber 140 in the form of the heat source 125 transfer. By applying heat from a heat source 125 on the heat transfer fluid is the heat transfer fluid in the common chamber 140 from a low-quality liquid-vapor mixture into a high-quality liquid-steam mixture or into saturated steam, while the heat transfer fluid passes through the common chamber 140 flows. In addition, the high temperature heat transfer fluid becomes in the second passage 123 cooled, while the heat transfer fluid high temperature near the common chamber 140 happens. While passing through the second passage 123 leaves the cooled Heat transfer fluid of high temperature the second outlet 130 and enters the condenser 14 one. The heat transfer fluid in the common chamber 140 leaves the recovery valve 19 at the first outlet 159 into the saturated steam line 28 as a liquid-vapor mixture of high quality or as a saturated vapor.

While in the aforementioned embodiment, a heat source 125 Heat that has been transferred from one compressor to the neighboring environment can be a source of heat 125 also include an active heat source, as previously defined.

In a preferred embodiment of the invention, the recovery valve comprises 19 a third passage 148 and a third inlet 126 , Third inlet 126 is with the outlet pipe 20 connected and receives heat transfer fluid of high temperature, which is the compressor 12 leaves. A first check valve (not shown) capable of controlling the flow of heat transfer fluid through the common chamber 140 It's near the first inlet 124 the common chamber 140 positioned. The third passage 148 connects the third inlet 126 with the common chamber 140 , A second check valve (not shown) is in the third passage 148 near the common chamber 140 positioned. In a preferred embodiment of the invention, the second check valve is a solenoid valve which is capable, in response to an electrical signal, of the flow of heat transfer fluid through the third passage 148 to end.

In accordance with one embodiment of the invention, the cooling system 10 be operated in a defrost mode by closing the first check valve, which is close to the first inlet 124 the common chamber 140 is positioned, and opening the second shut-off valve, which in the third passage 148 near the common chamber 140 is positioned. In defrost mode, high temperature heat transfer fluid exits the compressor 12 in the third inlet 126 and flows through the third passage 148 and enters the common chamber 140 one. The high temperature heat transfer fluid passes through the first outlet 159 of the recovery valve 19 removed and flows through the saturated steam line 28 to the evaporator 16 , The heat transfer fluid of high temperature has a temperature sufficient to the temperature of the evaporator 16 from about 50 to 120 ° F (27.8 to 66.7 ° C). The temperature rise is sufficient to frost from the evaporator 16 to eliminate and restore the heat transfer rate to desired operating levels.

During the Defrost cycle become oil deposits, which are contained in the system, heated and in the same flow direction worn as the heat transfer fluid. By hot Gas in forward flow direction blown through the system, the oil contained may eventually returned to the compressor. The name is Gas is going through the system at a relatively high speed migrate, which gives the gas little time to cool and so on to increase the defrosting efficiency. The defrosting method according to the invention with forward flow offers several advantages compared to the backward flow defrost method. For example use defrosting systems with reverse flow a check valve small diameter near the inlet of the evaporator. The check valve limits the flow of hot Gas in reverse direction and reduces its speed and thus its defrosting efficiency. About that In addition, the defrost method according to the invention avoids forward flow a pressure building up in the system during defrosting. Additionally have the reverse flow methods the tendency to drive oil contained in the system back into the expansion valve. That's not desirable because excessive oil in the Expansion bonding can cause the operation of the valve hinder. Thus, with the forward defrost, the pressure in the liquid line in all additional Cooling circuits, the additionally operated to the defrost cycle, not reduced.

professionals will understand that a vapor compression system, which according to the invention is arranged, with less heat transfer fluid can be operated as a comparably large system according to the state of the art Technology. By positioning the multifunction valve near the Condenser instead of near the evaporator is the saturated steam line filled with a vapor of relatively low density rather than a liquid with a relatively high density. Alternatively, by applying a heat source to the saturator vapor line the saturated steam line also filled with a vapor of relatively low density instead of a liquid of relatively high density. additionally Compensate prior art systems operating conditions at low temperature (eg in winter) by flooding the evaporator, to support a suitable head temperature at the expansion valve. In a preferred embodiment The invention provides a sufficient vapor pressure of the compression system easier to maintain in cold weather, because the multi-function valve is arranged in close proximity to the capacitor.

The defrost ability of the invention with forward flow offers numerous operational advantages as a result of improved defrost efficiency. For example, by driving trapped oil back into the compressor, liquid sludge is avoided, which has the effect of increasing the useful life of the device. In addition, reduced operating costs are achieved because less time is needed to defrost the system. Because the flow of hot gas can be stopped quickly, the system can be quickly switched back to normal cooling mode. When mature from the evaporator 16 eliminated, the temperature sensor detects 32 a temperature rise in the heat transfer fluid in the suction line 30 , When the temperature has risen to a predetermined point, the shut-off valve becomes 50 and the multifunction valve 18 closed. Once the heat transfer fluid again through the first passage 38 flows, cold saturated steam quickly returns to the evaporator 16 back to resume cooling operation.

professionals will realize that various modifications are made can, around the cooling system to enable the invention to meet a variety of applications. For example, cooling systems, those in grocery stores Typically, a number of cooling housings operate from a common one Compressor system can be operated. Likewise, in Applications, the cooling operation with high thermal loads require multiple compressors used to control the cooling capacity of the cooling system to increase.

A vapor compression system 64 According to another embodiment of the invention with a plurality of evaporators and a plurality of compressors is in 5 shown. To maintain the operating efficiency and cost advantages of the invention, the plurality of compressors, the condenser, and the multiple multifunction valves are in a control unit 66 contain. Saturated vapor lines 68 and 70 Supply saturated steam from the control unit 66 to evaporators 72 respectively. 74 , Evaporator 72 is in a first cooling housing 76 and evaporator 74 in a second cooling housing 78 accommodated. The first and second cooling housings 76 and 78 can be positioned next to each other or alternatively at a relatively large distance from each other. The exact position will depend on the specific application. For example, in a grocery store, the cooling housings are typically placed side by side along an island route. It is important that the cooling system of the invention be adaptable to a wide variety of operating environments. Partially this advantage is achieved because the number of components within each cooling housing is minimal. In a preferred embodiment of the invention, the cooling system may be used by avoiding the need to accommodate numerous operating components in the vicinity of the evaporator, where the available space is a minimum. This is especially advantageous for operation in retail stores where floor space is often limited.

During operation several compressors feed 80 Heat transfer fluid into an outlet manifold 82 , which with an outlet pipe 84 connected is. outlet pipe 84 feeds a capacitor 86 and has a first branch line 88 , which is a first multi-function valve 90 feeds, and a second branch line 92 , which is a second multi-function valve 94 fed. A bifurcated fluid line 96 feeds heat transfer fluid from the condenser 86 in the first and second multifunction valves 90 and 94 , The saturated steam line 68 connects the first multifunction valve 90 with the evaporator 72 and the saturator vapor line 70 connects the second multifunction valve 94 with the evaporator 74 , A fork-shaped suction line 98 connects the evaporators 72 and 74 with a collection multiple 100 , which has several compressors 80 fed. A temperature sensor 102 is on a first segment 104 the fork-shaped suction line 98 attached and sends signals to the first multi-function valve 90 , A temperature sensor 106 is on a second segment 108 the fork-shaped suction line 98 attached and sends signals to the second multi-function valve 94 , In a preferred embodiment of the invention, a heat source such. B. the heat source 25 to the saturator steam lines 68 and 70 be attached to ensure that the heat transfer fluid is the evaporator 72 and 74 enters as saturated steam.

Those skilled in the art will recognize that various modifications and variations of the vapor compression system 64 can be made to meet different cooling applications. For example, more than two evaporators can be incorporated into the system according to the general method in 5 , In addition, more condensers and more compressors can be added to the cooling system to further enhance cooling capability.

A multifunction valve 110 , which is arranged according to a further embodiment of the invention, is in 6 shown. Similar to the previous embodiment of a multi-function valve, the heat transfer fluid exiting the condenser in the liquid state enters a first inlet 122 and expands in an expansion chamber 152 , The flow of heat transfer fluid is through the valve assembly 154 measured. In the present embodiment, a solenoid valve 112 a fitting 114 who are in a common seating area 116 extends. In cooling mode, the valve extends 114 to the floor of the common seating area 116 and cold coolant is through a passage 118 to a common chamber 140 and then to an outlet 120 , In defrost mode, hot steam enters the second inlet 126 and flows through the common seating area 116 in the common chamber 140 and then to the outlet 120 , Multi-function valve 110 includes a reduced number of components because the design is such that a single shut-off valve is able to control the flow of hot steam and cold steam through the valve.

In yet another embodiment The invention may include the flow of liquefied heat transfer fluid from the fluid conduit be controlled by the multi-function valve through a check valve, which is housed in the first passage to the river of liquefied Heat transfer fluid in the saturator vapor line to lock. The flow of heat transfer fluid through the cooling system is controlled by a pressure valve, which in the suction line is arranged near the inlet of the compressor. Accordingly can the various functions of a multifunctional valve of the invention be carried out by separate components, in different Locations within the cooling system are positioned. All these variations and modifications will be considered by the present invention.

professionals will recognize that the vapor compression system and method, which are described herein in a variety of configurations can be implemented. For example, you can Compressor, condenser, multi-function valve and evaporator in housed in a single unit and housed in a walk-in refrigerator become. In this application, the capacitor extends through the wall of the walk-in refrigerator and ambient air outside of the refrigerator is used to heat transfer fluid to condense.

In another application the vapor compression system and method for air conditioning a Apartment or office be configured. In this application, a defrost cycle is not necessary because Icing of the evaporator is usually no problem.

In yet another application the vapor compression system and method of the invention is used be used to cool water. In this application, the evaporator is in the water to be cooled immersed. Alternatively, water can be pumped through tubes containing the evaporator coils are connected.

In another application the vapor compression system and method of the invention with a other system are cascaded to extremely low cooling temperatures to reach. For example, you can two systems with different heat transfer fluids together be connected so that the evaporator of the first system a Low temperature environment provides. A capacitor of the second system is in the low temperature environment and is used to heat transfer fluid in the second System to condense.

Multifunction valve or device 225 is in the 11 - 14 represented and generally by the reference numeral 225 designated. This embodiment works similar to that described in the 2 - 4 and 6 is described and generally with the reference numeral 18 is designated. As shown, this embodiment includes a main body or a main body 226 preferably as a one-piece structure with a pair of threaded sockets 227 . 228 which receive a pair of shut-off valves and collar devices, one of which is in 13 represented and with the reference numeral 229 is designated. This arrangement includes a threaded collar 230 , a seal 231 and a receiving element 223 with a central bore 233 for a solenoid activated check valve, which has a reciprocating valve pin 234 who is a feather 235 and a needle valve element 236 which comprises in a bore 237 a valve seat member 238 with an elastic seal 239 which is dimensioned to fit in a groove 240 of the housing 226 be sealed, a. A valve seat element 241 fits in a well 242 the valve seat member 238 , Valve seat member 241 includes a hole 243 connected to the needle valve element 236 cooperates to regulate the coolant flow.

A first inlet 244 (corresponding to the first inlet 24 in the embodiment described above) receives liquid coolant from the expansion valve 42 and a second inlet 245 (corresponding to the second inlet 26 of the previously described embodiment) receives hot gas from the compressor 42 during one defrost cycle. In a preferred embodiment, the Multifunk includes tion valve 225 the first inlet 244 , the outlet 248 , the common chamber 246 and the expansion valve 42 , as in 16 shown. expansion valve 42 can with the first inlet 244 be connected. The valve body 226 includes a common chamber 246 (according to the common chamber 40 in the embodiment described above). expansion valve 42 receives coolant from the condenser 14 , which then through the inlet 244 in a semicircular groove 247 which flows when the check valve 229 is open, in the common chamber 246 flows and the multifunction valve 225 through the outlet 248 (according to the outlet 41 in the embodiment described above) leaves.

How best in 11 to see includes the valve body 226 a first passage 249 (corresponding to the first passage 38 of the previously described embodiment), which has a first inlet 244 with the common chamber 246 combines. Similarly, a second passage connects 250 (corresponding to the second passage 48 of the previously described embodiment) the second inlet 245 with the common chamber 246 ,

As far as the operation of the multi-function valve or multifunction device 225 is concerned, reference is made to the previously described embodiment whose components operate in the same way during the cooling and defrosting cycles. In a preferred embodiment, the heat transfer fluid leaves the condenser 14 in the liquid state and flows through expansion valve 42 , As the heat transfer fluid flows through the expansion valve, the heat transfer fluid changes from a liquid to a liquid-vapor mixture. The heat transfer fluid enters the first inlet 244 as a liquid-vapor mixture and expands into the common chamber 246 , In a preferred embodiment, the heat transfer fluid expands in a direction away from the flow of the heat transfer fluid. Once the heat transfer fluid into the common chamber 246 expands, the liquid separates from the steam in the heat transfer fluid. The heat transfer fluid then leaves the common chamber 246 , Preferably, the heat transfer fluid leaves the common chamber 246 as a liquid and vapor, wherein a substantial amount of the liquid is separated from a substantial amount of vapor. The heat transfer fluid then flows through the outlet 248 and wanders through the saturated steam line 28 to the evaporator 16 , In a preferred embodiment, the heat transfer fluid then passes through the outlet 248 and enters the evaporator 16 at the first evaporation line 328 as described in detail below. Preferably, the heat transfer fluid migrates from the outlet 248 to the inlet of the evaporator 16 as a liquid and vapor, wherein a substantial amount of the liquid is separated from a substantial amount of vapor.

A pair of shut-off valves 229 Can be used to control the flow of heat transfer fluid or hot steam into the common chamber 246 to control. In cooling mode, the first shut-off valve 229 open to allow the coolant through the first inlet 244 and in the common chamber 246 and then to the outlet 248 to flow. In defrost mode is a second shut-off valve 229 opened to allow the hot steam through the second inlet 245 in the common chamber 246 and then to the outlet 248 to flow. While in the above embodiments, a multi-function valve 225 was described with multiple shut-off valves 229 , can be a multi-function valve 225 also be designed with only one shut-off valve. In addition, the multifunction valve 225 described with a second inlet 245 In order to allow the hot steam to flow through during the defrost mode, the multifunction valve can 225 even with only a first inlet 244 be constructed.

The multifunction valve includes a branch line 251 , as in 15 shown. branch line 251 is with the common chamber 246 connected and allows the heat transfer fluid in the common chamber 246 to the saturator vapor line 28 or the first evaporator line 328 to wander. branch line 251 It makes it possible for the liquid coming from the liquid-vapor mixture to enter the common chamber 246 entered, to the saturator vapor line 28 or the first evaporator line 328 to wander. Preferably, the branch line 251 with the bottom surface 252 the common chamber 246 connected, the floor area 252 the surface of the common chamber 246 which is closest to the ground.

Multi-function valve 225 can be dimensioned as specified in Table A below and as in 11 - 14 shown. The length of the common chamber 246 is defined as the distance from the outlet 248 to the back wall 253 , The length of the common chamber 246 is represented by the letter G, as in 11 shown. The common chamber 246 has a first portion adjacent to a second portion, with the first portion at the outlet 248 starts and the second section on the back wall 253 ends, as in 11 shown. The first inlet 244 and the outlet 248 Both are connected to the first section. The heat transfer fluid enters the common chamber 246 by the ers inlet 244 and in the first section of the common chamber 246 one. In a preferred embodiment, the first portion has a length less than or equal to about 75% of the length of the common chamber 246 , Preferably, the first portion has a length less than or equal to about 35% of the length of the common chamber 246 , TABLE A DIMENSIONS OF MULTI-FUNCTION VALVE Dimensions Inches (all unspecified dimensions +/- 0.015) Millimeters (all unspecified dimensions +/- 0,381) A 2500 63.5 B 2125 53975 C 1718 43637 D1 (diameter) 0812 20625 D2 (diameter) 0609 15469 D3 (diameter) 1688 42875 D4 (diameter) 1,312 (+/- 0.002) 33,325 (+/- 0.051) D5 (diameter) 0531 13487 e 0406 10312 F 1062 26975 G 4500 114.3 H 5000 127 I 0781 19837 3 2500 63.5 K 1250 31.75 L 0466 11836 M 0.812 (+/- 0.005) 20.6248 (+/- 0.127) R1 (radius) 0125 3175

In a preferred embodiment, the heat transfer fluid passes through the expansion valve 42 and then enters the inlet of the evaporator 16 a, like in 16 shown. In this embodiment, the evaporator comprises 16 a first evaporator line 328 , an evaporator snake 21 and a second evaporator line 330 , The first evaporator line 328 is between the outlet 248 and the evaporator coil 21 positioned as in 16 shown. A second evaporator line 330 is between the evaporator coil 21 and a temperature sensor 32 positioned. The evaporator coil 21 is any conventional snake or conventional device that absorbs heat. The multifunction valve 18 is preferably connected to and adjacent to the evaporator 16 , In a preferred embodiment, the evaporator comprises 16 a part of a multi-function valve 18 , such as B. the first inlet 244 , the outlet 248 and the common chamber 246 , as in 16 shown. Preferably, the expansion valve 42 adjacent to the evaporator 16 positioned. Heat transfer fluid exits the expansion valve 42 and then enters directly into the evaporator 16 at the inlet 244 one. Once the heat transfer fluid the expansion valve 42 leaves and at the inlet 244 in the evaporator 16 occurs, the temperature of the heat transfer fluid is at an evaporation temperature, ie, the heat transfer fluid begins to absorb heat while passing through the expansion valve 42 flows.

After flowing through the inlet 244 , the common chamber 246 and the outlet 248 the heat transfer fluid enters the first evaporator conduit 328 one. Preferably, the first evaporator line 328 isolated. The heat transfer fluid then leaves the first evaporator conduit 28 and enters the evaporator coil 21 one. After leaving the evaporator coil 21 the heat transfer fluid enters the second evaporator conduit 330 one. The heat transfer fluid exits the second evaporator conduit 330 and the evaporator 16 at the temperature sensor 32 ,

Preferably, each element within the evaporator absorbs 16 for example, the saturator vapor line 28 , the multifunction valve 18 and the evaporator coil 21 , Heat. In a preferred embodiment, once the heat transfer fluid is through the expansion valve, the heat transfer fluid is 42 at a temperature within 11 ° C (20 ° F) of the temperature of the heat transfer fluid in the evaporator coil 21 , In another preferred embodiment, the temperature of the heat transfer fluid in each element is within the evaporator 16 , such as B. the saturator vapor line 28 , the multifunction valve 18 and the evaporator coil 21 within 11 ° C (20 ° F) of the temperature of the heat transfer fluid in each other element within the evaporator 16 ,

As is known to those skilled in the art, each element of the cooling system described above 10 , z. B. the evaporator 16 , the liquid line 22 and the suction line 30 , scaled and dimensioned to meet a variety of load requirements.

In a preferred embodiment, the cooling capacity of the heat transfer fluid is in the cooling system 10 equal to or greater than the cooling capacity of a conventional system.

Without further execution may be assumed that a skilled person using the preceding Description can use the invention in its full extent. The following Examples serve more to describe the invention and are intended to be limit the scope of protection in any way.

EXAMPLE I

A 5 ft (1.52 m) Tyler freezer was fitted with a multi-function valve in a refrigeration circuit and a standard expansion valve was soldered into a bypass line so that the refrigeration cycle could be operated as a conventional refrigeration system and as an XDX refrigeration system according to the present invention , The refrigeration cycle described above was equipped with a saturator vapor line having an outside diameter of about 0.375 inches (0.953 cm) and an effective tube length of about 10 feet (3048 m). The refrigeration cycle was operated by a hermetic Copeland compressor with a cooling capacity of approximately 1/3 ton (338 kg). A feeler piston was attached to the suction line about 18 inches from the compressor. The cycle was 28 oz. (792 g) R-12 refrigerant charged, available from DuPont Company. The refrigeration cycle was also populated with a bypass line extending from the discharge line of the compressor to the saturator steam line for the forward flow defrost (see 1 ) extended. All temperature measurements of the cooled ambient air were conducted using a CPS Data Logger with a CPS temperature sensor located in the center of the cooling housing, approximately 4 inches above the floor.

XDX system operation at medium temperature

The nominal operating temperature of the evaporator was 20 ° F (-6.7 ° C) and the nominal operating temperature of the condenser was 120 ° F (48.9 ° C). The evaporator handled a cooling load of about 3000 Btu / hr (21 g cal / s). The multifunction valve meters coolant into the saturated steam line at a temperature of approximately 20 ° F (-6.7 ° C). The probe piston was set to maintain approximately 25 ° F (13.9 ° C) overheating of the vapor flowing in the suction line. The compressor fed pressurized refrigerant into the outlet line at a condensation temperature of about 120 ° F (48.9 ° C) and a pressure of about 172 lbs / in ² (118.560 N / m ² ).

XDX system operation at low temperature

The nominal operating temperature of the evaporator was -5 ° F (-20.5 ° C) and the nominal operating temperature of the condenser was 115 ° F (46.1 ° C). The evaporator handled a cooling load of about 3000 Btu / hr (21 g cal / s). The multi-function valve metered approximately 2975 ft / min (907 km / min) of refrigerant into the saturator vapor line at a temperature of approximately -5 ° F (-20.5 ° C). The probe piston was set to maintain a 20 ° F (11.1 ° C) overheat of the steam flowing in the suction line. The compressor delivered about 2299 ft / min (701 m / min) of the pressurized refrigerant to the outlet line at a condensation temperature of about 115 ° F (46.1 ° C) and a pressure of about 161 lbs / in ² (110.977 N / m ² ). The XDX system was operated in essentially the same low temperature mode as in the medium temperature mode, except that the fans in the Tyler freezer were defrosted for 4 minutes after defrosting to remove heat from the evaporator coil and remove water from the coil allow.

The XDX cooling system was operated for a period of about 24 hours in operation at medium temperature and about 18 hours during operation at low temperature. The temperature of the ambient air inside the Tyler freezer was during the 23-hour Test period measured approximately every minute. The air temperature was while the test period measured continuously, while the cooling system in both the cooling mode as well as in defrost mode. During the defrost cycles was the cooling circuit operated in defrost mode until the temperature of the sensor piston approximately Reached 50 ° F (10 ° C). The statistics of the temperature measurement appear in the table I below.

Conventional system - operation at medium temperature with electric defrost

The Tyler freezer described above was equipped with a bypass line extending between the compressor discharge line and the suction line for the defrost stretched. The bypass line was with a solenoid valve stocked, around the flow of high temperature coolant shut off in the line. An electric heating element was during this Test instead of the solenoid energized. A standard expansion valve was installed immediately adjacent to the evaporator inlet and the temperature sensing piston was at the suction line immediately adjacent to the evaporator outlet appropriate. The sensor piston was set to about 6 ° F (3.33 ° C) overheating of the steam flowing in the suction line to maintain. In front In operation, the system was about 48 oz. (1.36 kg) of the coolant R-12 loaded.

The conventional cooling system was running at medium temperature for a period of about 24 hours operated. The temperature of the ambient air in the Tyler freezer was during the 24 hour Test period measured approximately every minute. The air temperature was while the test period measured continuously, while the cooling system in both the cooling mode as well as in defrost mode with backward flow was operated. While the defrost cycles became the refrigeration cycle operated in defrost mode until the temperature of the sensor piston approximately Reached 50 ° F (10 ° C). The temperature measurement statistics appear in Table I below.

Conventional system - operation at medium temperature with air defrost

The Tyler freezer described above was with a receiver stocked, to provide a suitable fluid supply to the expansion valve and a liquid line dryer was installed for an additional Coolant reserve. The expansion valve and the sensor piston were positioned at the same locations as in the one described above Defrost system with reverse flow. The sensor piston was set to approximately 8 ° F (4.4 ° C) overheating the steam, the flows in the suction line, maintains. Before operation, the system was about 34 oz. (0.966 kg) of the coolant R-12 loaded.

• 1) Ein Abtauzyklus während der 23 stündigen Testperiode
• 2) Drei Abtauzyklen während der 24 stündigen Testperiode

The conventional refrigeration system was operated at medium temperature operation for a period of approximately 24 1/2 hours. The ambient air temperature in the Tyler freezer was measured approximately every minute during the 24 1/2 hour test period. The air temperature was measured continuously during the test period while the cooling system was operating in both the cooling mode and the air defrost mode. In accordance with the conventional approach, four defrost cycles were programmed, each lasting approximately 36 to 40 minutes. The statistics in the temperature measurement appear in Table I below. TABLE I Cooling Temperatures (° F / ° C) XDX ^{1 )} Mean temperature XDX ¹⁾ Low temperature Conventional ²⁾ Electric defrost Conventional ²⁾ Air defrost average 38.7 / 3.7 4.7 / -15.2 39.7 / 4.3 39.6 / 4.2 standard deviation 0.8 0.8 4.1 4.5 variance 0.7 0.6 16.9 20.4 Area 7.1 7.1 22.9 26.0

• 1) One defrost cycle during the 23 hour test period
• 2) Three defrost cycles during the 24 hour test period

As shown above the XDX cooling system according to the invention a desired one Temperature in the freezer with less temperature variation than the conventional one System. The standard deviation, the variance and the range of Temperature measurements during the test period are significantly lower than the of conventional systems. This result stands for operation XDX system at both medium and low temperatures.

During defrost cycles, the temperature rise in the freezer was monitored to determine the maximum temperature within the freezer. This temperature should be as close as possible to the operating cooling temperature to prevent spoilage of food products stored in the freezer. The maximum defrost temperature for the XDX system and for the conventional systems is shown in Table II below. TABLE II Maximum defrost temperature (° F / ° C) XDX Mean temperature Conventional Electric Defrost Conventional air defrost 44.4 / 6.9 55.0 / 12.8 58.4 / 14.7

EXAMPLE II

The Tyler cabinets was configured as described above and additionally with electric defrosting stocked. The operating test at low temperature was as described above carried out and the time taken by the cooling unit needed was to get to the cooling temperature to come was measured.

A separate test was then performed using the electrical defrosting circuit to defrost the evaporator. The time required by the XDX system and a defrost electrical system to complete the defrost and ramp to the set 5 ° F (-15 ° C) operating temperature point appears in Table III below. TABLE III Time required to reach the cooling temperature of 5 ° F (-15 ° C) following XDX Conventional system with electric defrost Defrost duration (min) 10 36 Return time (min) 24 144

As required above the XDX system using the forward flow defrost through the Multifunction valve less time to completely defrost the evaporator, and much less time to reach the cooling temperature again.

Consequently it is obvious that here in accordance provided with the invention, a vapor compression system which has the advantages outlined above in full to disposal provides. Although the invention has been described and illustrated by Reference to specific illustrative embodiments thereof, It is not intended that the invention be limited to these illustrative Embodiments is limited. Professionals will recognize that variations and modifications are made can be without departing from the invention. For example, halogen-free coolant be used such. As ammonia and the like can also be used become. It is therefore intended that all such variations and modifications, which are included in the scope of the attached claims fall into the invention.

Claims (45)

Vapor compression system, comprising: a compressor ( 12 ) for increasing the pressure and the temperature of a heat transfer fluid; a first outlet conduit ( 20 ), which is the compressor ( 12 ) connects to a capacitor; a fluid line ( 22 ), the capacitor ( 14 ) with a first inlet of an expansion valve ( 42 ) connects; the expansion valve ( 42 ) is adapted to expand the heat transfer fluid to form an expanded heat transfer fluid; a saturated steam line ( 28 ), which has an outlet of the expansion valve ( 42 ) with an evaporator ( 16 ) connects; a suction line ( 30 ), the evaporator ( 16 ) with the compressor ( 12 ) connects; characterized in that a heat source ( 25 ) is applied to the expanded heat transfer fluid prior to its entry into the evaporator, thereby achieving conversion of a substantial portion of the heat transfer fluid to a saturated vapor prior to its entry into the evaporator; (a) where the compressor ( 12 ) and / or the capacitor ( 14 ) are in close proximity to the expansion valve so that the fluid line ( 22 ) relatively short and the saturated steam line ( 28 ) is relatively longer than the liquid line, whereby the heat source is the heat generated by the compressor ( 12 ) and / or the capacitor ( 14 ) is produced; or (b) wherein the heat source is an active heat source. Vapor compression system, comprising: a compressor ( 12 ) for increasing the pressure and the temperature of a heat transfer fluid; a first outlet conduit ( 20 ), which is the compressor ( 12 ) with a capacitor ( 14 ) connects; a fluid line ( 22 ), the capacitor ( 14 ) with a first inlet of an expansion valve ( 42 ) connects; the expansion valve ( 42 ) is configured so that the heat transfer fluid can expand to form an expanded heat transfer fluid; a saturated steam line ( 28 ), which has an outlet of the expansion valve ( 42 ) with an evaporator ( 16 ) connects; a suction line ( 30 ), the evaporator ( 16 ) with the compressor ( 12 ) connects; characterized in that a heat source ( 25 ) is applied to the expanded heat transfer fluid prior to its entry into the evaporator, whereby conversion of a substantial portion of the heat transfer fluid into a saturated vapor prior to its entry into the evaporator is achieved, the expansion valve being part of a recovery valve (US Pat. 19 ) is which recovery valve ( 19 ) comprises a first inlet ( 124 ), which provides fluid access for the heat transfer fluid into a common chamber ( 14 ) and a first outlet ( 159 ) having a fluid outlet for the heat transfer fluid from the common chamber ( 140 ), and wherein a part of the first outlet line ( 20 ) to the common chamber ( 14 ) is arranged adjacent, whereby the heat source ( 25 ) Heat is from the compressor ( 12 ) and / or the capacitor ( 14 ) and through the first outlet line ( 20 ) to the common chamber ( 140 ) is transmitted. A vapor compression system according to claim 1, wherein the expansion valve ( 42 ) Part of a multifunctional valve ( 18 ), and wherein the first inlet of the expansion valve ( 42 ) with a first inlet ( 24 ) of the multifunction valve ( 18 ) and the outlet of the expansion valve ( 42 ) with an outlet ( 41 ) of the multifunction valve ( 18 ) connected is. A vapor compression system according to claim 3, wherein the multi-function valve ( 18 ) further comprises: a first passage connecting the outlet of the expansion valve ( 42 ) with a first expansion chamber ( 52 ) connects; a second pass ( 38 ), which is the first expansion chamber ( 52 ) with a second expansion chamber ( 40 ) connects; a third passage connecting the second expansion chamber ( 40 ) with the outlet ( 41 ) of the multifunction valve ( 18 ), wherein the heat transfer fluid has a first volumetric expansion in the first expansion chamber (FIG. 52 ) and a second volumetric expansion in the second expansion chamber ( 40 ) learns. Vapor compression system according to one of the preceding Claims, being the heat source is sufficient to be substantially about (3 to 5 lbs / min) 1.36 to To convert 2.27 kg / min of R-12 into a saturated vapor. A vapor compression system according to claim 3, further comprising a second outlet conduit which connects the compressor ( 12 ) with a second inlet ( 26 ) of the multifunction valve ( 18 ) connects. A vapor compression system according to claim 6, wherein the multi-function valve ( 18 ) further comprises a first passage connecting the liquid line ( 22 ) with the first inlet of the expansion valve ( 42 ) connects a second pass ( 48 ), the second outlet from the compressor ( 12 ) with the saturated steam line ( 28 ) and a slide valve ( 50 ), which in the second passage ( 48 ) is arranged so that hot steam from the compressor into the saturated steam line ( 28 ) can flow when the slide valve ( 50 ) is open. A vapor compression system according to claim 6, further comprising a temperature sensor ( 32 ) located in the intake line ( 30 ) and effective with the multifunction valve ( 18 ) connected is. A vapor compression system according to claim 8, wherein: the first inlet of the multi-function valve (10 18 ) is blocked by a first solenoid valve; the second inlet of the multifunction valve ( 18 ) is blocked by a second solenoid valve; and the expansion valve ( 42 ) from the temperature sensor ( 32 ) is activated. A vapor compression system according to claim 8, further comprising a device housing ( 34 ) and a refrigeration cabinet ( 36 ), where the compressor ( 12 ), the capacitor ( 14 ), the multifunction valve ( 18 ) and the temperature sensor ( 32 ) in the device housing ( 34 ) and wherein the evaporator ( 16 ) in the refrigeration cabinet ( 36 ) is located. A vapor compression system according to any one of the preceding claims, wherein the compressor ( 12 ) a variety of compressors ( 80 ), each of which has an inlet branch ( 100 ) with the suction line ( 30 ) and each of which is in one with the outlet ( 84 ) omits associated outlet branching. A vapor compression system according to claim 6, wherein the multi-function valve ( 18 ) one with the first inlet ( 24 ) associated first passage ( 38 ), wherein the first passage ( 38 ) the expansion valve ( 42 ) disposed therein and from a first valve ( 46 ), a second passage ( 48 ) connected to the second inlet ( 26 ) and from the second valve ( 50 ) and a common chamber ( 40 ), and wherein the first and second passages ( 38 ) 48 ) in the common chamber ( 40 ) end up. A vapor compression system according to claim 12, further comprising a pressure regulating valve disposed in the intake passage (16). 30 ), wherein the first valve ( 46 ) in the multifunction valve ( 18 ) comprises a check valve. A vapor compression system according to claim 12, further comprising a temperature sensor ( 32 ) connected to the suction line ( 25 ) and effective with the multifunction valve ( 18 ) connected is. A vapor compression system according to claim 1, wherein the heat source ( 25 ) to the saturated steam line ( 28 ) is applied. A vapor compression system according to any one of the preceding claims, further comprising a meter connected to the intake manifold (16). 30 ) and effectively with the expansion valve ( 42 ) connected is. A vapor compression system according to claim 3, further comprising: an outlet conduit (16); 20 ), which is the compressor ( 12 ) to a second inlet ( 26 ) of the multifunction valve ( 18 ) couples; and a meter attached to the intake manifold ( 30 ) and effective with the multifunction valve ( 18 ) connected is. A vapor compression system according to claim 15 or 17, further comprising a control unit ( 34 ) and a refrigeration cabinet ( 36 ), where the compressor ( 12 ) and the capacitor ( 14 ) in the control unit ( 34 ) are housed, and wherein the evaporator ( 16 ), the multifunction valve ( 18 ) and the temperature sensor ( 32 ) in the refrigeration cabinet ( 36 ) are located. A vapor compression system according to any one of claims 8, 12 or 17, further comprising: a variety of evaporators ( 72 . 74 ); a variety of multifunction valves ( 90 . 94 ); a plurality of saturated steam lines ( 68 . 70 ), wherein each saturated steam line of one of the plurality of multi-function valves ( 90 . 94 ) with one of the plurality of evaporators ( 72 . 74 ), a variety of suction lines ( 104 . 108 ), each suction line ( 104 . 108 ) one of the plurality of evaporators ( 72 . 74 ) with the compressor ( 12 ), whereby a heat source ( 25 ) is applied to each of the saturated steam lines and wherein each of the plurality of intake lines ( 104 . 108 ) a built-in temperature sensor ( 102 . 106 ) to send a signal to one of the plurality of multifunction valves ( 90 ) 94 ) pass on. Vapor compression system according to claim 2, wherein the expansion valve ( 142 ) adjacent to the first inlet ( 124 ) and wherein the expansion valve ( 142 ) the heat transfer fluid volumetrically into the common chamber ( 140 ) expands. A vapor compression system according to claim 20, wherein the recovery valve (16) 19 ) further comprises: a second inlet ( 127 ), the second inlet ( 127 ) fluid access for a high temperature heat transfer fluid to a passage adjacent the common chamber ( 123 ) provides; and a second outlet ( 130 ), the second outlet ( 130 ) provides a fluid exit for the high temperature heat transfer fluid from the second passage. A vapor compression system according to claim 21, wherein said second inlet ( 127 ) with an outlet conduit ( 20 ) of a compressor ( 12 ) connected is. A vapor compression system according to claim 21, wherein the second outlet ( 127 ) with an inlet of a condenser ( 14 ) connected is. A vapor compression system according to claim 21, wherein the recovery valve (16) 19 ) further comprises: a third inlet ( 126 ), the third inlet ( 126 ) a fluid access for a heat transfer fluid of high temperature in the common chamber ( 140 ) provides; a first slide valve ( 46 ), which can stop the flow of heat transfer fluid through the common chamber when in a closed position, the first gate valve 46 ) near the first inlet ( 124 ) of the common chamber ( 140 ) is arranged; and a second slide valve ( 50 ) which directs the flow of high temperature heat transfer fluid through the common chamber ( 140 ) when it is in an open position, the second slide valve ( 50 ) near the third inlet ( 126 ) of the common chamber ( 140 ) is arranged. A vapor compression system according to claim 24, wherein the recovery valve (16) 19 ) by displacing the first slide valve ( 46 ) in the closed position and the second slide valve ( 50 ) in the open position an evaporator ( 16 ) can defrost. A vapor compression system according to claim 3, wherein the evaporator ( 16 ) also a part of the multifunction valve ( 18 ). Vapor compression system according to one of the preceding claims, wherein the evaporator ( 16 ) comprises a first evaporator conduit, an evaporator coil and a second evaporator conduit. A vapor compression system according to claim 26, wherein the multi-function valve ( 18 ) to the evaporator ( 16 ) adjoins. A vapor compression system according to claim 3, wherein the multi-function valve ( 18 ) in the immediate vicinity of the capacitor ( 12 ) is located. The vapor compression system of claim 1, wherein the expansion valve further comprises: a common chamber ( 40 ) for expanding the heat transfer fluid, the common chamber comprising a first part adjacent to a second part, the first part having the first inlet and the outlet and the second part having a rear wall opposite the outlet, the outlet having a fluid outlet for the first Heat transfer fluid from the common chamber ( 40 ), the expansion valve ( 42 ) produces a heat transfer fluid in which a substantial amount of liquid is separate and separate from a substantial amount of vapor. A vapor compression system according to claim 30, wherein the first part is no more than 75% of the length of the common chamber ( 40 ) having. A vapor compression system according to claim 3, wherein the multi-function valve ( 18 ) further comprises: a first expansion chamber ( 52 ), the first inlet ( 24 ) of the multifunction valve ( 18 ) fluid access via a first passage to the first expansion chamber ( 52 ) provides a second pass ( 38 ), which is the first expansion chamber ( 52 ) and a second expansion chamber ( 40 ) connects together; a slide valve ( 46 ), which in the second pass ( 38 ) is located; and a third passage, which communicates a fluid exit from the second expansion chamber ( 40 ) to the outlet ( 41 ) of the multifunction valve ( 18 ) provides; where the expansion valve ( 42 ) in the first passage adjacent to the inlet ( 24 ) of the multifunction valve ( 18 ) is located. A vapor compression system according to claim 32, wherein the expansion valve ( 42 ) further comprises a valve assembly ( 54 ) includes a portion projecting into the first passage to regulate the amount of fluid entering the first expansion chamber (10). 52 ) entry. A vapor compression system according to claim 32, wherein the gate valve ( 46 ) comprises a solenoid valve. A vapor compression system according to claim 33, wherein said first expansion chamber ( 52 ), the second expansion chamber ( 40 ) and the second passage ( 38 ) are arranged so that a liquefied heat transfer fluid, which in the first expansion chamber ( 52 ), a first volumetric expansion in the first expansion chamber ( 52 ) and a second volumetric expansion in the second expansion chamber ( 40 ) and the second expansion chamber ( 40 ) leaves as a substantially saturated vapor. A vapor compression system according to claim 32, wherein the multi-function valve ( 18 ) further comprises: a second inlet ( 26 ); a fourth round ( 48 ), the second inlet ( 26 ) with the second expansion chamber ( 40 ) couples; and a second slide valve ( 50 ), which in the fourth round ( 48 ) is located. A method of operating a vapor compression system, comprising: compressing a heat transfer fluid in a compressor ( 12 ) to a relatively high temperature and high pressure to form a compressed heat transfer fluid, flowing the compressed heat transfer fluid through a first compressor discharge line (16); 20 ) to a capacitor ( 14 ); Condensing the compressed heat transfer fluid in the condenser ( 14 ) to form a condensed heat transfer fluid; Flowing the condensed heat transfer fluid from the condenser ( 14 ) through a fluid line into the inlet ( 24 ) of an expansion valve ( 42 ); Receiving the heat transfer fluid at the inlet of the expansion valve ( 42 ) in a liquid state; Converting the condensed heat transfer fluid in the expansion valve ( 42 ) to a low pressure state to form an expanded heat transfer fluid, wherein the condensed heat transfer fluid is in the expansion valve (10). 42 ) undergoes volumetric expansion; Flowing the expanded heat transfer fluid from the outlet ( 41 ) of the expansion valve ( 42 ) through a saturated steam line ( 28 ) to the inlet of an evaporator ( 16 ); characterized by: applying a heat source ( 25 ) to the expanded heat transfer fluid, the heat source being an active heat source and / or a heat source generated by the compressor, condenser and / or outlet conduit, and receiving the heat transfer fluid at the inlet of the evaporator (FIG. 16 ) in a saturated vapor state, the heat source ( 25 ) applied to the expanded heat transfer fluid is sufficient to evaporate a portion of the heat transfer fluid to form a saturated vapor before the heat transfer fluid enters the evaporator (10). 16 ), and wherein the saturated vapor substantially the evaporator ( 16 ) and returning the saturated vapor through a suction line ( 30 ) in the compressor ( 12 ). The method of claim 37, wherein the flowing of the expanded heat transfer fluid to the Saturated steam line ( 28 ) comprises: measuring the temperature of the heat transfer fluid in the intake line ( 30 ) at a location close to the compressor ( 12 ); and forwarding a signal to the expansion valve ( 42 ). The process of claim 37, wherein at least 5% of the heat transfer fluid is vaporized before the heat transfer fluid enters the evaporator (15). 16 ), and wherein a portion of the heat transfer fluid is in a liquid state upon exiting the evaporator. A method according to claim 37, wherein the expansion valve ( 42 ) a part of a multi-function valve ( 18 ) and the method further comprises: flowing the compressed heat transfer fluid from the compressor ( 12 ) through a second compressor outlet line to the second inlet (FIG. 26 ) of the multifunction valve ( 18 ); Flowing the compressed heat transfer fluid from the second inlet ( 26 ) of the multifunction valve ( 18 ) to an outlet of the multi-function valve ( 18 ); and flowing the expanded heat transfer fluid from the outlet ( 41 ) of the multifunction valve ( 18 ) to the evaporator ( 16 ), the multi-function valve comprising: a first inlet ( 24 ) for receiving the heat transfer fluid in a liquid state: the second inlet ( 26 ) for receiving the heat transfer fluid in a gaseous state: a first passage ( 38 ), the first inlet ( 24 ) with a common chamber ( 40 ), the first passage ( 38 ) the expansion valve located therein ( 42 ) and from a first valve ( 46 ) is blocked; a second pass ( 48 ), the second inlet ( 26 ) with the common chamber ( 40 ), the second passage ( 48 ) from a second valve ( 50 ) is blocked; and a third passage connecting the common chamber ( 40 ) with an outlet of the multi-function valve ( 18 ) couples. The method of claim 40, further comprising defrosting the evaporator ( 16 ) by closing the first valve and opening the second valve ( 50 ) in the multifunction valve ( 18 ) to control the flow of heat transfer fluid in the first pass (FIG. 38 ) and stop the flow of heat transfer fluid from the compressor ( 12 ) through the second passage ( 48 ) to the common chamber ( 40 ) to initiate. The method of claim 37, wherein the flow of the heat transfer fluid into the saturated steam line ( 28 ) comprises: measuring the temperature of the heat transfer fluid in the intake line ( 30 ) at a point close to the compressor ( 12 ); and actuating the expansion valve ( 42 ) according to the temperature. The method of claim 40, further comprising Stream the heat transfer fluid with approximately 1.36 to 2.27 kg / min (approx 3 to 5 lbs / min), the heat transfer fluid a fluid comprising the group consisting of R-12 and R-22 selected is. Process according to claim 40, wherein the evaporator ( 16 ) is sized to provide a cooling capacity of about 84 g cal / s (about 12,000 Btu / hr). The method of claim 43, wherein the heat transfer fluid is conveyed through the saturated vapor line (16). 28 ) flows at a rate of about 762 m / min to 1128 m / min (about 2500 ft / min to 3700 ft / min).